In recent years, there have been suggested work machines such as excavators and bulldozers equipped with GPS (global positioning system) or the like to detect their locations, compare positional information from the GPS with construction information indicating landforms of construction sites to determine the postures of the work machines by computing processes and control the motion of the work machines, or compares the postures or positions of the work machines with the construction information and display guidance about the construction status on a monitoring device (for example, refer to Patent Literatures 1 and 2). Construction work using such work machines is called computerized construction. According to the computerized construction, even inexperienced operators of work machines can carry out high-accuracy construction work. Skilled operators can perform high-efficiency construction work by computerized construction. According to the computerized construction, it is possible to significantly reduce conventionally required land surveys and finishing stake settings.